The present invention relates generally to high power amplifiers, and more particularly, to an improved coplanar waveguide structure that forms an improved inductor for use with monolithic microwave integrated circuit high power amplifiers.
Prior art relating to monolithic microwave integrated circuit (MMIC) high power amplifier output matching circuit designs includes the following. Certain prior art MMIC high power amplifiers use microstrip based circuitry. Circuit loss diminishes with wider microstrip line width. The loss of the output matching circuit is of the order of 0.5 dB for conventional X-band power MMIC amplifiers. Microstrip based circuitry is not compatible with flip-chip module assembly techniques.
Other prior art MMIC high power amplifiers use a coplanar waveguide with a very wide signal carrying strip to meet dc current carrying requirements. Current crowding of coplanar waveguide with large strip-to-gap ratio leads to a low Q factor, and higher circuit loss. Flip-chip amplifier efficiency suffers when such lower Q, critical resonant circuit elements are employed.
It would therefore be desirable to have a coplanar waveguide structure for use with monolithic microwave integrated circuit high power amplifiers that improves upon conventional designs.